Dual venturi for combustor

ABSTRACT

The present invention relates to a dual venturi for a combustor and, more specifically, to a dual venturi for a combustor which can control, in two stages, the amount of gas and air supplied to a burner provided in a water heater, wherein a motor and a damper are combined in such a manner that the damper is rotated by the driving of the motor, and thus the damper simultaneously opens or closes the inlet for secondary air and gas, thereby efficiently controlling the quantity of heat. The dual venturi comprises: a housing which has a first gas inlet and a second gas inlet on one side of the upper part thereof, and which has an interior divided by a partition wall such that a first passage and a second passage are formed; and an opening and closing means which is disposed in the housing, has an upper part connected to the second gas inlet such that gas flows therein, and controls the flow of air and gas by closing or opening the second passage as a damper is rotated by a motor provided on the exterior of the housing.

TECHNICAL FIELD

The present invention relates to a dual venturi for a combustionapparatus, and more particularly, to a dual venturi for a combustionapparatus, capable of effectively controlling a heating value sincerespective amounts of gas and air supplied to a burner provided in awater heater are controlled in a two-step manner and a motor is coupledto a damper so that the damper simultaneously opens or closes inlets forsecondary air and gas along with rotation of the damper by driving ofthe motor.

BACKGROUND ART

In general, combustion apparatuses such as boilers and water heaters forthe purpose of use of heating and hot water are classified into an oilboiler, a gas boiler, an electric boiler and a water heater depending onthe fuel it is supplied with, and are variously developed and usedaccording to installation applications.

In such combustion apparatuses, particularly the gas boiler and thewater heater typically use a bunsen burner or a premixed burner to burngas fuel. The premixed burner among others has a combustion method ofmixing gas and air in a mixing ratio for optimal combustion and thensupplying a mixture (air+gas) to a flame hole section so that themixture is burned.

In addition, the performance of the combustion apparatuses is evaluatedas a TDR (Turn-Down Ratio). The TDR refers to “a ratio of maximum gasconsumption to minimum gas consumption” in a gas combustion device inwhich an amount of gas is variably controlled. For example, when themaximum gas consumption is 24,000 kcal/h and the minimum gas consumptionis 8,000 kcal/h, the TDR is 3:1. The TDR is constrained by whether flameis stably maintained to some degree under minimum gas consumption.

In the gas boiler and the water heater, convenience for use of heatingand hot water is increased as the TDR becomes greater. That is, when theburner is actuated in a region in which the TDR is small (namely, theminimum gas consumption is high) and loads of heating and hot water aresmall, the combustion apparatuses are frequently turned on/off. For thisreason, variation in temperature control is increased and durability ofthe apparatuses is deteriorated. Thus, in order to improve theseproblems, various methods for improving the TDR of the burner applied tothe combustion apparatuses have been developed.

In such a modulating control burner, valves allowing for supply of gasare mainly classified into an electrical modulating gas valve controlledby current values and a pneumatic modulating gas valve controlled bydifferential pressures generated during supply of air.

The pneumatic modulating gas valve controls an amount of gas supplied tothe burner by differential pressures generated when air required forcombustion is supplied to the burner by a blower. In this case, air andgas required for combustion are mixed in a gas-air mixer and thensupplied to the burner in a mixture (air+gas) form.

In the gas-air mixer of the gas burner using the above pneumaticmodulating gas valve, the TDR is basically constrained by a factor suchas a relation between gas consumption Q and differential pressure ΔP.The relation between flow rate and differential pressure of a fluid isgenerally as follows.

Q=k√{square root over (ΔP)}

That is, as seen in the above relational equation, in order to doublethe flow rate of the fluid, the differential pressure has to bequadrupled.

Accordingly, the ratio of pressure differences has to be defined as 9:1for defining the TDR as 3:1 and the ratio of pressure differences has tobe defined as 100:1 for defining the TDR as 10:1. However, there is aproblem in that it is impossible to infinitely increase gas supplypressure.

In order to resolve the problem in which the gas supply pressure may notbe infinitely increased, there is disclosed a method which increases theTDR of the gas burner by respectively dividing passages, through whichair and gas are supplied, into two or more regions and by opening andclosing each passage of gas injected into the burner.

DISCLOSURE Technical Problem

The present invention has been made in view of the above problems, andit is an object of the present invention to provide a dual venturi for acombustion apparatus, capable of achieving high operation durability,easy manufacturing, and a reduction in manufacturing cost while the dualventuri is compact by simplification of a complicated structure.

Technical Solution

In accordance with an aspect of the present invention, a dual venturifor a combustion apparatus includes a housing having a first gas inletand second gas inlet formed at one side of an upper portion thereof anddivided therein by a partition wall to have a first passage and a secondpassage, and an opening and closing unit provided within the housing,connected to the second gas inlet at an upper portion thereof such thatgas is introduced into the opening and closing unit, and controllingflows of air and gas by closing or opening the second passage along withrotation of a damper by a motor provided at an outer side of thehousing.

In the aspect, the opening and closing unit may include a tubular guidetube having one or more concave guides formed on an inner wall thereof,a tubular moving body having convex guides formed on an outer wallthereof to correspond to the concave guides so that the moving bodymoves within the guide tube in a longitudinal direction of the guidetube, a gas outlet formed at a distal end thereof to communicate withthe second gas inlet, and a moving body cam having a cam shape formed onan outer surface thereof, a valve body having the damper formed on anouter surface thereof, a gas outlet formed at a side of the damper, anda valve body cam formed at an inner side thereof in a shapecorresponding to the moving body cam such that the valve body camengages with the moving body cam, valve body being coupled to the motor,a spring provided within the moving body to elastically support themoving body, and a cap supporting the spring and coupled to an upperportion of the guide tube.

In the aspect, when the motor is rotated and the moving body cam formedat the moving body is rotated, respective tip portions of the movingbody cam and the valve body cam may come into contact with each other topush the moving body up, with the consequence that the opening andclosing unit may open the gas outlet and simultaneously open the secondpassage by rotation of the damper of the valve body.

In the aspect, the valve body may further include a sealing member forsealing an inner lower end thereof.

In the aspect, the motor may be a synchronous motor.

Advantageous Effects

In accordance with the present invention having the above features, thefollowing effects may be obtained.

First, heating values such as low heating values or high heating valuesmay be selectively generated by a water heater as necessary and a usermay control the heating values such as low heating values or highheating values as necessary. Therefore, fuel costs may be reduced.

Secondly, an inner portion of a housing is divided by a partition wallto form a first passage and a second passage so that only primary airand gas flow in the first passage and only secondary air and gas flow inthe second passage. Therefore, it may be possible to easily adjust a TDRby regulating the flows of air and gas in the second passage.

Thirdly, since a second gas outlet is opened and closed and at the sametime the second passage is also opened and closed by rotation of a valvebody, a structure may be significantly simplified.

DESCRIPTION OF DRAWINGS

FIG. 1A is a perspective view illustrating a dual venturi for acombustion apparatus according to an embodiment of the presentinvention.

FIG. 1B is a cross-sectional view taken along line A-A of FIG. 1A.

FIG. 2A is a cross-sectional view taken along line B-B of FIG. 1A.

FIG. 2B is a view illustrating a state in which a moving body is movedupward in FIG. 2A.

FIGS. 3A and 3B are perspective views illustrating the moving body ofFIG. 1B.

FIG. 4 is a perspective view illustrating a valve body of FIG. 1B.

FIGS. 5A and 5B are perspective views illustrating an opening andclosing unit.

FIG. 6 is a cross-sectional view taken along line C-C of FIG. 5A.

FIG. 7 is a view illustrating a position relation between a motor and alimited switch of the motor included in the dual venturi for acombustion apparatus according to the embodiment of the presentinvention.

MODE FOR INVENTION

Reference will now be made in detail to embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings. The present invention may, however, be embodied in differentforms and should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the present invention to those skilled in the art. Accordingly,the drawings are not necessarily to scale and in some instances,proportions may have been exaggerated in order to clearly illustratefeatures of the embodiments. Throughout the disclosure, like referencenumerals refer to like parts throughout the various figures andembodiments of the present invention. In addition, detailed descriptionsof functions and constructions well known in the art may be omitted toavoid unnecessarily obscuring the gist of the present invention.

Hereinafter, a dual venturi for a combustion apparatus according to anexemplary embodiment of the present invention will be described indetail with reference to the accompanying drawings.

FIG. 1A is a perspective view illustrating a dual venturi for acombustion apparatus according to an embodiment of the presentinvention. FIG. 1B is a cross-sectional view taken along line A-A ofFIG. 1A. FIG. 2A is a cross-sectional view taken along line B-B of FIG.1A. FIG. 2B is a view illustrating a state in which a moving body ismoved upward in FIG. 2A. FIGS. 3A and 3B are perspective viewsillustrating the moving body of FIG. 1B. FIG. 4 is a perspective viewillustrating a valve body of FIG. 1B. FIGS. 5A and 5B are perspectiveviews illustrating an opening and closing unit. FIG. 6 is across-sectional view taken along line C-C of FIG. 5A. FIG. 7 is a viewillustrating a position relation between a motor and a limited switch ofthe motor included in the dual venturi for a combustion apparatusaccording to the embodiment of the present invention.

Referring to FIGS. 1 to 6, the dual venturi for a combustion apparatusaccording to the embodiment of the present invention includes acylindrical housing 10 which has a first gas inlet 14 and second gasinlet 15 formed at one side of an upper portion thereof and is dividedtherein by a partition wall 13 to have a first passage 11 and a secondpassage 12.

In addition, a discharge port 16 formed at the housing 10 is coupledwith a turbofan (not shown) for supplying a mixture (gas+air) introducedfrom the first and second passages 11 and 12 to a burner.

Meanwhile, the housing 10 is coupled, at an inner central portionthereof, with an opening and closing unit 100 which is connected to thesecond gas inlet 15 at an upper portion thereof such that gas isintroduced into the opening and closing unit 100 and controls the flowsof air and gas by closing or opening the second passage 12 along withrotation of a damper 142 by a motor 180 provided at an outer side of thehousing 10. In addition, the motor 180 is preferably configured of asynchronous motor. This enables manufacturing costs to be reduced bygenerally using the cheap synchronous motor.

The opening and closing unit 100 includes a tubular guide tube 130having one or more concave guides 131 formed on an inner wall thereof,and a tubular moving body 120 which has convex guides 122 formed on anouter wall thereof to correspond to the concave guides 131 so that themoving body 120 moves within the guide tube 130 in a longitudinaldirection of the guide tube 130, a gas outlet 123 formed at a distal endthereof to communicate with the second gas inlet 15, and a moving bodycam 121 having a cam shape formed on an outer surface thereof. An innersurface of the guide tube 130 and an outer surface of the moving body120 are formed in a stepped shape, and a sealing ring 146 is coupled tothe stepped portion to prevent leakage of gas.

In addition, the opening and closing unit 100 includes a valve body 140which is coupled to a lower portion of the moving body 120, has thedamper 142 formed on an outer surface thereof, a gas outlet 143 formedat a side of the damper 142, and a valve body cam 141 formed at an innerside thereof in a shape corresponding to the moving body cam 121 suchthat the valve body cam 141 engages with the moving body cam 121, and iscoupled to the motor 180.

Furthermore, the opening and closing unit 100 includes a spring 160formed inside the moving body 120 to elastically support the moving body120 and a cap 170 which supports the spring 160 and is coupled to anupper portion of the guide tube 130.

Meanwhile, a connection member 190 is coupled to a lower portion of thevalve body 140. The connection member 190 is coupled to a rotary shaft181 of the motor 180 to transfer driving force generated by the motor180 to the valve body 140. In addition, a sealing member 145 for sealingan inner lower end of the valve body 140 is inserted into a lower end ofthe valve body 140.

Meanwhile, the outer side of the housing 10 is further provided with themotor 180 for rotating the valve body 140 coupled to the connectionmember 190 by coupling of the rotary shaft 181 and the connection member190. The motor 180 provides torque to the valve body 140. The rotaryshaft 181 has protrusions 182 formed at intervals of 90 degrees and theprotrusions 182 operate a limit switch 201 along with rotation of themotor 180 such that a rotation angle of the valve body 140 iscontrolled. The limit switch 201 is provided inside a switch box 200 andthe switch box 200 is interposed between the housing 10 and the motor180.

Hereinafter, an operation state of the dual venturi for a combustionapparatus of the present invention having the above configuration willbe described.

First, an operation in which only primary gas and air are supplied froma water heater is performed in such a way that the damper 142 of thevalve body 140 is rotated perpendicular to a direction in which air andgas in the second passage 12 flow so that the second passage 12 isblocked, and at the same time a concave portion of the moving body cam121 and a convex portion of the valve body cam 141 are in contact with aconvex portion of the moving body cam 121 and a concave portion of thevalve body cam 141, thereby allowing the gas outlet 123 of the movingbody 120 to come into contact with the sealing member 145 so that thesecond gas passage is maintained in a blocked state and the gas outlet123 is also maintained in a blocked state, as shown in FIGS. 2A and 5A.

Accordingly, since a mixture of air and gas is introduced into theturbofan only through the first gas inlet 14 and the first passage 11, acombustion apparatus may be actuated by means of a low heating value.

Meanwhile, in order to actuate the combustion apparatus by means of ahigh heating value, power is applied to the motor 180 and the motor 180rotates the valve body 140 by 90 degrees such that the damper 142 isrotated to correspond to a longitudinal direction of the second passage12, as shown in FIGS. 2B and 5B.

At the same time, since the valve body 140 is rotated and the valve bodycam 141 formed therein is also rotated, the respective convex portions(tip portions) of the valve body cam 141 and the moving body cam 121come into contact with each other, thereby allowing the moving body cam121 to be pushed up along with rotation of the valve body cam 141. Inthis case, since the convex guides 122 are inserted into the concaveguides 131, the moving body 120 is easily moved upward within the guidetube 130.

Accordingly, since the valve body 140 is rotated in a direction equal tothe longitudinal direction of the second passage 12, the second passage12 is opened and secondary gas is simultaneously introduced through thegas outlet 143 by decoupling of the lower end of the gas outlet 123 ofthe moving body 120 from the sealing member 145, as shown in FIGS. 2Band 5B. Here, the secondary gas is mixed with the air and gas introducedthrough the second passage 12 and is then mixed with the air and gasintroduced through the first passage 11 and the first gas inlet 14, sothat a large amount of mixture is generated and the mixture isintroduced into the turbofan. As a result, the combustion apparatus maybe actuated by means of a high heating value.

Subsequently, when the motor 180 rotates the valve body 140 by 90degrees in order to actuate the combustion apparatus by means of a lowheating value again, the valve body 140 is returned to the state shownin FIGS. 1B, 2A, and 5A. Consequently, the second passage 12 and the gasoutlet 143 are blocked and, as such, the combustion apparatus isactuated by means of a low heating value. Here, the spring 160 providedin the moving body 120 serves to increase restoration of the moving body120 when the second passage 12 is closed by rotation of the valve body140.

Hereinafter, a description will be given with respect to the limitswitch 201 for controlling rotation of the motor 180 driving the dampersuch that the combustion apparatus is actuated by means of the lowheating value or the high heating value.

Referring to FIG. 7, the rotary shaft 181 of the motor 180 has theprotrusions 182 which are protrudingly formed on an outer peripheralsurface thereof at intervals of 90 degrees and the limit switch 201 hasmovable protrusions 202 formed to be located on the same circumferenceas the protrusions 182. When the protrusions 182 press the movableprotrusions 202 while rotating at intervals of 90 degrees, the limitswitch 201 causes a short circuit current and, as such, rotation of themotor 180 is stopped.

Therefore, when the combustion apparatus is actuated, the protrusions182 are rotated by 90 degrees to press the movable protrusions 202.Then, the limit switch 201 is turned off to stop rotation of the motor180 and the valve body 140 is also stopped. As a result, the secondpassage 12 is opened or closed.

Although the present invention has been described with respect to theillustrative embodiments of the dual venturi for a combustion apparatus,it should be understood that numerous other modifications andapplications may be devised by those skilled in the art that will fallwithin the intrinsic aspects of the embodiments. More particularly,various variations and modifications are possible in concreteconstituent elements of the embodiments. In addition, it is to beunderstood that differences relevant to all variations, equivalents, andalternatives fall within the spirit and scope of the present disclosuredefined in the appended claims.

DESCRIPTION OF REFERENCE NUMERALS

10: housing, 11: first passage

12: second passage, 13: partition wall

14: first gas inlet, 15: second gas inlet

100: opening and closing unit, 120: moving body

121: moving body cam, 122: convex guide

130: guide tube, 131: concave guide

140: valve body, 141: valve body cam

142: damper, 143: gas outlet

145: sealing member, 146: sealing ring

160: spring, 170: cap

180: motor, 181: rotary shaft

182: protrusion, 190: connection member

200: switch case, 201: limit switch

202: movable protrusion

1. A dual venturi for a combustion apparatus, comprising: a housing (10) having a first gas inlet (14) and second gas inlet (15) formed at one side of an upper portion thereof and divided therein by a partition wall (13) to have a first passage (11) and a second passage (12); and an opening and closing unit (100) provided within the housing (10), connected to the second gas inlet (15) at an upper portion thereof such that gas is introduced into the opening and closing unit (100), and controlling flows of air and gas by closing or opening the second passage (12) along with rotation of a damper (142) by a motor (180) provided at an outer side of the housing (10).
 2. The dual venturi of claim 1, wherein the opening and closing unit (100) comprises: a tubular guide tube (130) having one or more concave guides (131) formed on an inner wall thereof; a tubular moving body (120) having convex guides (122) formed on an outer wall thereof to correspond to the concave guides (131) so that the moving body (120) moves within the guide tube (130) in a longitudinal direction of the guide tube (130), a gas outlet (123) formed at a distal end thereof to communicate with the second gas inlet (15), and a moving body cam (121) having a cam shape formed on an outer surface thereof; a valve body (140) having the damper (142) formed on an outer surface thereof, a gas outlet (143) formed at a side of the damper (142), and a valve body cam (141) formed at an inner side thereof in a shape corresponding to the moving body cam (121) such that the valve body cam (141) engages with the moving body cam (121), valve body (140) being coupled to the motor (180); a spring (160) provided within the moving body (120) to elastically support the moving body (120); and a cap (170) supporting the spring (160) and coupled to an upper portion of the guide tube (130).
 3. The dual venturi of claim 1, wherein when the motor (180) is rotated and the moving body cam (121) formed at the moving body (120) is rotated, respective convex portions of the moving body cam (121) and the valve body cam (141) come into contact with each other to push the moving body (120) up, with the consequence that the opening and closing unit (100) opens the gas outlet (143) and simultaneously opens the second passage (12) by rotation of the damper (142) of the valve body (140).
 4. The dual venturi of claim 2, wherein the valve body (140) further comprises a sealing member (145) for sealing an inner lower end thereof.
 5. The dual venturi of claim 1, wherein the motor (180) is a synchronous motor.
 6. The dual venturi of claim 2, wherein when the motor (180) is rotated and the moving body cam (121) formed at the moving body (120) is rotated, respective convex portions of the moving body cam (121) and the valve body cam (141) come into contact with each other to push the moving body (120) up, with the consequence that the opening and closing unit (100) opens the gas outlet (143) and simultaneously opens the second passage (12) by rotation of the damper (142) of the valve body (140).
 7. The dual venturi of claim 2, wherein the motor (180) is a synchronous motor. 